HT instruments HT14N - Manual (Page 8)

HT-14N
EN - 7
4.2.5. Decibel measurement
WARNING
Maximum input for AC/DC voltage is 500V.
Do not attempt to take any voltage measurement that exceeds the limits.
Exceeding the limits could cause electrical shock and damage the
multimeter. Disconnect test leads from the circuit under test prior to select a
different range.
1. Select a proper range for AC voltage (25, 250 or 500 DC V) according with the
following table:
dB Range (dB)
0 - 30 20 -50 26 –56
AC Range (V) 25 250 500
Correction Factor (db) 0 20 26
2. If the dB range is not known beforehand, set the range switch to the highest range and
work down.
3. Insert the two long ends of test leads to the desired circuit.
4. The reading will be displayed in the corresponding red scale. The measured dB will get
from the following formula:
dB = dB (read on dB scale) + Correction Factor
Note: for absolute dB measurements, circuit impedance must be 600
Ω, 0db = 1mW
dissipated in a 600
Ω load.
For the signal with DC component, connect a capacitor with capacity > 0.1F between test
probes and circuit under test.
4.2.6. Battery check for 1.5 V and 9.0V
WARNING
Maximum input for DC voltage is 10V. Do not attempt to take any voltage
measurement that exceeds the limits. Exceeding the limits could cause
electrical shock and damage the multimeter.
1. Select a proper range for Battery check (1.5, 9.0 V).
2. Insert the two long ends of test leads to the battery under test, then reading will be
displayed in the “BATT” scale. (“RED” color for bad, “GREEN” color for good).